M16C62 Datasheet, PDF (117/231 Pages) Renesas Technology Corp – SINGLE-CHIP 16-BIT CMOS MICROCOMPUTER

UART2 Special Mode Register
Mitsubishi microcomputers
M16C / 62 Group (80-pin)
SINGLE-CHIP 16-BIT CMOS MICROCOMPUTER
The acknowledgment non-detection interrupt refers to the interrupt that occurs when the SDA terminal
level is detected still staying “H” at the rising edge of the 9th transmission clock. The acknowledgment
detection interrupt refers to the interrupt that occurs when SDA terminal’s level is detected already went
to “L” at the 9th transmission clock. Also, assigning 1 1 0 1 (UART2 reception) to the DMA1 request factor
select bits provides the means to start up the DMA transfer by the effect of acknowledgment detection.
Bit 1 of the UART2 special mode register (037716) is used as the arbitration loss detecting flag control bit.
Arbitration means the act of detecting the nonconformity between transmission data and SDA terminal
data at the timing of the SCL rising edge. This detecting flag is located at bit 3 of the UART2 reception
buffer register (037F16), and “1” is set in this flag when nonconformity is detected. Use the arbitration lost
detecting flag control bit to choose which way to use to update the flag, bit by bit or byte by byte. When
setting this bit to “1” and updated the flag byte by byte if nonconformity is detected, the arbitration lost
detecting flag is set to “1” at the falling edge of the 9th transmission clock.
If update the flag byte by byte, must judge and clear (“0”) the arbitration lost detecting flag after complet-
ing the first byte acknowledge detect and before starting the next one byte transmission.
Bit 3 of the UART2 special mode register is used as SCL- and L-synchronous output enable bit. Setting
this bit to “1” goes the P71 data register to “0” in synchronization with the SCL terminal level going to “L”.
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